Updated positive interim data from a Phase II/III study of subcutaneous (SQ) prophylactic Factor VIIa variant marzeptacog alfa (activated) (MarzAA)for haemophilia A or B.- Catalyst Biopsciences Inc.

Catalyst Biosciences, Inc. announced updated positive interim data from its Phase II/III study of subcutaneous (SQ) prophylactic Factor VIIa (FVIIa) variant marzeptacog alfa (activated) (MarzAA), being developed for the treatment of hemophilia A or B with inhibitors. The data will be delivered in an oral presentation at the 2018 Hemophilia Drug Development Summit being held on August 15-16 in Boston.

�The ongoing study of subcutaneous MarzAA for the treatment of hemophilia A or B with inhibitors continues to demonstrate positive interim results, as reflected in the clinical update provided at this year�s Hemophilia Drug Development Summit,� said Nassim Usman, Ph.D., chief executive officer of Catalyst. �We have not observed any bleeds or anti-drug antibodies in the two additional subjects who most recently completed dosing with 30 �g/kg MarzAA, as well as in the previously reported individual who completed 50 days of dosing with 60 �g/kg MarzAA. The data from these three individuals support the efficacy of MarzAA to reduce annualized bleed rates after daily subcutaneous injections. Importantly, to date we have not observed any injection site reactions nor any anti-drug antibodies after more than 200 subcutaneous doses of MarzAA.�

Dr. Howard Levy, chief medical officer of Catalyst, presented the updated interim results from the MarzAA Phase II/III trial in which five of up to 12 subjects have been enrolled. Since initial interim data was announced at the ISTH conference in July 2018, in which one subject with a historic annualized bleed rate (ABR) of 26.7 had completed the trial with no bleeds after 50 days of treatment with 60 �g/kg MarzAA, two additional subjects have now completed the trial. One of these subjects, who has a historic ABR of 16.6, had no bleeds during treatment with 30 �g/kg MarzAA for 50 days. No ADAs have been detected to date, with safety data for the final 10 days of dosing still being collected for this subject. The second subject, who has a historic ABR of 15.9, had no bleeds during treatment with 30 �g/kg MarzAA for 44 days. No ADAs have been detected to date.